A U.S. regulator can proceed with lawsuits accusing HSBC Holdings Plc and Nomura Holdings Inc of misleading Fannie Mae and Freddie Mac into buying mortgage-backed securities that later turned toxic, a federal judge ruled on Thursday.

The decision from U.S. District Judge Denise Cote in Manhattan clears the way for HSBC to face trial Sept. 29 in a case by the Federal Housing Finance Agency that the bank has estimated could expose it to $1.6 billion in liability.

FHFA launched 18 lawsuits in 2011 over about $200 billion in mortgage-backed securities. HSBC, Nomura and Royal Bank of Scotland Group Plc are the remaining banks being sued by the regulator.